Actually the heart rate during arrhythmias (abnormal rhythms), is actually a less complex signal in the information theoretic sense. This was noticed about 30

Actually the heart rate during arrhythmias (abnormal rhythms), is actually a less complex signal in the information theoretic sense. This was noticed about 30 years ago and has been widely studied in the heart rate variability literature. Healthy heart rate signals are complex in the sense that it has structural richness and correlations across multiple time scales. However arrhythmias appear as either random patterns in heart rate, such as in the case of atrial fibrillation; or as repeating, somewhat deterministic patterns, such as in common ventricular arrhythmias like bigeminy or trigemeny or in congestive heart failure where the heart rate become abnormally regular.